Spatial Taming and Trapping of Molecules

分子的空间驯化和捕获

• 批准号: 9986027
• 负责人: Dudley Herschbach
• 金额: $ 53.3万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-15 至 2005-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9986027&HistoricalAwards=false
• 关键词: Spatial; Taming; Trapping; Molecules

Dudley Herschbach is supported by the Experimental Physical Chemistry Program to develop an apparatus for manipulating and trapping molecules with very low translational energies. This will be accomplished by molecular beam expansion cooling of gases exiting from the periphery of a high speed contra-rotating rotor such that the rotortip motion cancels out the expansion velocity. There is also the option of increasing the velocity above thermal by co-rotating the rotor. The basic viability was established using Xe and the technique is being developed and extends to other gases (O2, Cl2, HCl and CO). Five developments being made are to: 1) improve the rotor construction and eliminate design weaknesses; 2) increase the pressure for the supersonic expansion to achieve lower temperatures; 3) improve the vacuum to reduce slow molecule scattering; 4) develop techniques for collecting the slow molecules and 5) use a pulsed gas nozzle to improve the uni-directional nature of the supersonic beam. In parallel with these developments, there are a) studies of chemistry at low temperatures, specifically that of OH, b) use of inhomogeneous static and laser fields to scatter or focus the slow particles and c) demonstrations of the de Broglie nature of the slow particles by molecular diffraction.The studies are developing a device in which molecules can be cooled down to very low temperatures, as low as one degree above absolute zero of temperature. At these temperatures, the molecules have speeds of a few tens of meters per second and have wavelengths large compared with their size. This entirely changes the nature of the reactive collisions between molecules, opening up a new realm of chemical behavior. The device is such that the speed of the molecules can be increased continuously, enabling the effect of energy on the process to be determined and the change-over to conventional behavior to be observed.

达德利·赫施巴赫在实验物理化学计划的支持下，开发了一种装置，用于操纵和捕获具有非常低平动能的分子。这将通过分子束膨胀冷却从高速反向旋转转子外围流出的气体来实现，这样旋翼尖端的运动抵消了膨胀速度。也有增加速度以上的选项，通过共旋转转子热。使用Xe建立了基本的可行性，该技术正在开发并扩展到其他气体（O2, Cl2， HCl和CO）。正在进行的五个发展是：1)改进转子结构，消除设计弱点；2)增加超声速膨胀的压力以达到较低的温度；3)提高真空度，减少缓慢的分子散射；4)发展收集慢分子的技术；5)使用脉冲气体喷嘴来改善超音速光束的单向性。在这些发展的同时，有a)低温下的化学研究，特别是OH的研究，b)使用非均匀静态和激光场散射或聚焦慢粒子，c)通过分子衍射证明慢粒子的德布罗意性质。研究人员正在开发一种设备，可以将分子冷却到非常低的温度，低至绝对零度以上一度。在这样的温度下，分子的速度为每秒几十米，波长也比它们的大小大。这完全改变了分子间反应性碰撞的性质，开辟了化学行为的新领域。这种装置可以使分子的速度不断增加，从而确定能量对过程的影响，并观察到向传统行为的转变。